Inverter generator

ABSTRACT

A generator includes an internal combustion engine including an engine block including a cylinder including a piston, a crankshaft configured to rotate about a crankshaft axis in response to movement by the piston, and a spark plug configured to periodically generate a spark to ignite fuel in the cylinder to control the movement of the piston. The generator further includes an alternator including a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power, a controller configured to control a rate of fuel supply to the internal combustion engine, and a switch configured to selectively enable the flow of a first type of fuel into the cylinder and disable the flow of a second type of fuel, wherein the controller is configured to receive an indication of a fuel type based on a position of the switch.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.17/719,046, filed Apr. 12, 2022, which is a continuation-in-part of U.S.patent application Ser. No. 17/336,711, filed Jun. 2, 2021, which claimsthe benefit of and priority to U.S. Provisional Patent Application No.63/034,069, filed Jun. 3, 2020, all of which are hereby incorporated byreference in their entireties.

BACKGROUND

The present invention relates generally to the field of standbygenerators, and more particularly to the field of inverter generators.

SUMMARY

One exemplary embodiment relates to a standby generator including astandby housing defining a cavity and an internal combustion engine. Theinternal combustion engine includes an engine block including a cylindercomprising a piston, an engine housing at least partially covering theengine block, and a crankshaft configured to rotate about a verticalcrankshaft axis in response to movement by the piston. The standbygenerator also includes an alternator comprising a rotor and a stator,the rotor configured to rotate with the rotation of the crankshaft togenerate alternating current electrical power, a controller comprising arectifier configured to convert the alternating current to a directcurrent and an inverter configured to convert the direct current to aclean alternating current electrical power, and a transfer switchconfigured to receive the clean alternating current electrical powerfrom the controller and at least one of grid power from an electricalgrid, solar power from a solar panel assembly, or battery power from abattery, and configured to supply power to an electrical load. Theinternal combustion engine, the alternator, and the controller arepositioned within the cavity of the standby housing for protection fromthe external environment.

Another exemplary embodiment relates to a standby generator including astandby housing defining a cavity and an internal combustion engine. Theinternal combustion engine includes an engine block including a cylindercomprising a piston, an engine housing at least partially covering theengine block, a crankshaft configured to rotate about a verticalcrankshaft axis in response to movement by the piston, and a spark plugconfigured to periodically generate a spark to ignite fuel in thecylinder to control the movement of the piston. The standby generatoralso includes an alternator positioned within an alternator housing andcomprising a rotor and a stator, the rotor configured to rotate with therotation of the crankshaft to generate alternating current electricalpower, a controller positioned within the alternator housing andincluding a rectifier configured to convert the alternating current to adirect current and an inverter configured to convert the direct currentto a clean alternating current electrical power, a transfer switchconfigured to receive the clean alternating current electrical powerfrom the controller and at least one of grid power from an electricalgrid, solar power from a solar panel assembly, or battery power from abattery, and configured to supply power to an electrical load. Thecontroller is configured to control spark generation timing of the sparkplug. The internal combustion engine, the alternator, and the controllerare positioned within the cavity of the standby housing for protectionfrom the external environment.

Still another exemplary embodiment relates to a standby generatorincluding a standby housing defining a cavity and an internal combustionengine. The internal combustion engine includes an engine blockincluding a cylinder comprising a piston, an engine housing at leastpartially covering the engine block, a crankshaft configured to rotateabout a vertical crankshaft axis in response to movement by the piston,and a spark plug configured to periodically generate a spark to ignitefuel in the cylinder to control the movement of the piston. The standbygenerator also includes an alternator comprising a rotor and a stator,the rotor configured to rotate with the rotation of the crankshaft togenerate alternating current electrical power, a battery configured tosupply power to the alternator, and a controller including a rectifierconfigured to convert the alternating current to a direct current and aninverter configured to convert the direct current to a clean alternatingcurrent electrical power. The rotor is further configured to rotate thecrankshaft using power from the battery to start the internal combustionengine. The internal combustion engine, the alternator, and thecontroller are positioned within the cavity of the standby housing forprotection from the external environment.

This summary is illustrative only and is not intended to be in any waylimiting. Other aspects, inventive features, and advantages of thedevices or processes described herein will become apparent in thedetailed description set forth herein, taken in conjunction with theaccompanying figures, wherein like reference numerals refer to likeelements.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a rear view of a standby generator, according to an exemplaryembodiment.

FIG. 2 is a side view of the standby generator of FIG. 1 .

FIG. 3 is a top view of the standby generator of FIG. 1 .

FIG. 4 is a schematic view of a twin cylinder assembly present in thestandby generator of FIG. 1 .

FIG. 5 is a partial exploded view of the standby generator of FIG. 1 .

FIG. 6 is a perspective view of a tubular frame of the standby generatorof FIG. 1 .

FIG. 7 is a perspective view of a muffler of the standby generator ofFIG. 1 .

FIG. 8 is a perspective view of an alternator assembly of the standbygenerator of FIG. 1 .

FIG. 9 is a perspective view of an engine housing of the standbygenerator of FIG. 1 .

FIG. 10 is a schematic view of a controller of the standby generator ofFIG. 1 .

FIG. 11 is a front perspective view of a standby housing associated withthe standby generator of FIG. 1 .

FIG. 12 is a front perspective view of a standby housing associated withanother standby generator, according to an exemplary embodiment.

FIG. 13 is a perspective view of the standby generator of FIG. 12 , withthe standby housing removed.

FIG. 14 is another perspective view of the standby generator of FIG. 13, detailing an inverter and other electronic components within thestandby generator.

FIG. 15 is another perspective view of the standby generator of FIG. 13, detailing an airflow pattern through the standby generator.

FIG. 16 is another perspective view of the standby generator of FIG. 13, detailing an engine and alternator used by the standby generator.

FIG. 17 is another perspective view of the standby generator of FIG. 13.

FIG. 18 is a perspective view of the standby housing of FIG. 12 ,depicting an access door to the inverter of FIG. 14 .

FIG. 19 is a perspective view of a standby generator, according to anexemplary embodiment.

FIG. 20 is a perspective view of an internal combustion engine andalternator assembly of the standby generator of FIG. 19 .

FIG. 21 is a perspective view of an internal combustion engine andalternator assembly of the standby generator of FIG. 19 .

FIG. 22 is an exploded perspective view of an internal combustion engineand alternator assembly of the standby generator of FIG. 19 .

FIG. 23 is a partially exploded view of a standby generator, accordingto an exemplary embodiment.

FIG. 24 is a schematic view of the standby generator of FIG. 19 .

FIG. 25 is a flow diagram of a method of operating a standby invertergenerator.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplaryembodiments in detail, it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for the purpose of description onlyand should not be regarded as limiting.

Referring to the figures generally, a standby inverter generator isshown according to an exemplary embodiment. Inverter generators outputalternating current (AC) and that current is then converted to directcurrent (DC), and then inverted back to clean AC power that maintains apure sine wave at the required voltage and frequency (e.g., 120V at 60Hz). On an inverter generator, the engine is connected to an alternator.The alternator produces AC power from the rotary motion produced by theengine and provides the AC power to a rectifier. The rectifier convertsthe AC power to DC power and provides the DC power to capacitors. Thecapacitors smoothen (e.g., filter) the DC power, which can then beinverted back into clean AC power at the desired frequency and voltage.The resultant AC power produced by the inverter generator is muchcleaner power (i.e., purer sine waves) than is typical with aconventional generator. Using inverter generators, sensitive deviceslike microprocessors can be supplied with electricity produced by theinverter generator. Supplying devices with a relatively poor quality ofelectricity may damage a device or cause the device to malfunction.Accordingly, inverter generators may be useful to provide AC power incertain applications (e.g., to power medical devices, high performancecomputers, etc.) that traditional generators may not be suitable for.

The inverter generators shown and described throughout this applicationare also more fuel efficient than conventional generators. The invertergenerators shown and described herein can adjust engine speed (e.g.,drive shaft rotational speed) to meet a required electrical power load.Accordingly, when relatively low power loads are experienced, the enginespeed can be reduced, which in turn lowers the fuel consumption of thegenerator as well as the emissions produced by the generator. Invertergenerators may also reduce noise relative to conventional generators.Quieter engines, special mufflers, and sound-dampening technology may beused on inverter generators to reduce noise relative to conventionalgenerators. In addition, conventional units generally run at a constantspeed to produce electricity with the desired characteristics.Accordingly, a constant noise is produced by conventional generators.Because inverter generators can adjust the electrical characteristics ofthe power produced by the inverter generator, the engine within theinverter generator can throttle back when the load is light to save fueland reduce noise caused by the unit.

Referring to FIGS. 1-4 , a standby inverter generator 20 is shownaccording to an exemplary embodiment. The inverter generator 20 includesan internal combustion engine, shown as engine 22, an alternatorassembly 24, a controller 26, a muffler 28, and a fuel connection 30.The inverter generator 20 is positioned within and coupled to a standbyhousing 100, which is configured to be positioned alongside a home orbuilding. As depicted in FIGS. 1-3 and 5 and explained in detail below,the inverter generator 20 is coupled to a floor panel 102 of the standbyhousing 100.

To generate electricity, the engine 22 draws fuel through the fuelconnection 30 and into an engine block 32. Fuel is directed through theengine block 32 into one or more cylinders 34, which house pistons 36.Fuel is supplied into cylinder heads 38 (e.g., with an injector, like anelectronic fuel injector (EFI)), mixed with air, and compressed betweenthe cylinder head 38 and piston 36. The gaseous fuel and air mixture isthen ignited by a spark plug (not shown) that extends into the cylinderhead 38. Ignition of the fuel and air within the cylinder head 38 causesthe gases within the cylinder head 38 to rapidly expand, which drivesthe piston 36 away from the cylinder head 38 and along a cylinder axis40 defined by the cylinder 34 the piston 36 is received within. Thecoupling between the pistons 36 and a crankshaft 42 of the engine 22causes the crankshaft 42 to rotate about its vertical crankshaft axis 44in response to piston movement about the cylinder axes 40. As depictedin FIG. 4 , the engine block 32 defines two cylinders 34 that areangularly offset from one another (e.g., arranged in a V-shape) aboutthe crankshaft axis 44. Exhaust from the gaseous fuel and air ignitionis directed outward from cylinder head 38 through the muffler 28.

The rotary motion of the crankshaft 42 about the crankshaft axis 44caused by the reciprocating pistons 36 can then be used by thealternator assembly 24 to generate electricity. The alternator assembly24 includes a stator 46 and a rotor 48. The rotor 48 is coupled to thecrankshaft 42 so that the rotor 48 rotates in unison with the crankshaft42. In some examples, the rotor 48 includes magnets (e.g., permanentmagnets) extending around a portion of the rotor 48 to produce magneticfields within the alternator assembly 24. As the rotor 48 rotates withinthe stator 46, the magnetic fields created by the magnets on the rotor48 rotate as well to produce a rotating magnetic flux. The stator 46includes a series of coils 50 (e.g., turned copper wire) spaced aboutits circumference to interact with and electromagnetically opposerotational motion of the rotor 48. Accordingly, when the rotor 48 andassociated magnets rotate within the stator 46, the rotating magneticflux produced by the rotor 48 will induce a current within the coils 50.The spacing between the magnets on the rotor 48 and the coils 50 withinthe stator 46 and the rotary motion of the rotor 48 generates an ACelectrical power output.

The AC electrical power output by the alternator assembly 24 is directedupwardly along one or more wires to the controller 26. As depicted inFIG. 10 , the controller 26 includes both a rectifier 104 and aninverter 106 to transform and condition the AC electrical power receivedfrom the alternator assembly 24. AC electrical power is first deliveredto the rectifier 104, which transforms the AC electrical power to DCpower. The DC power is then provided from the rectifier 104 to theinverter 106. The inverter 106 inverts the DC power from the rectifierinto a cleaner (e.g., higher quality) and more widely useful ACelectrical power at a desired frequency and voltage (e.g., 120 VAC at 60Hz). The generated three phase AC electrical power can then be outputfrom the standby inverter generator 20 and used to power variouselectronics and building systems. The inverter 106 can be neutral bondedto a ground wire (not shown).

Returning to FIGS. 1-4 and with additional reference to FIGS. 5-9 and 11, the structure of the standby inverter generator 20 is shown inadditional detail. As explained above, the standby inverter generator 20is coupled to the floor panel 102 of the standby housing 100. Thestandby inverter generator 20 can be coupled to and supported bymultiple structures that are bolted or otherwise removably coupled tothe floor panel 102. For example, an alternator stand 108 and a tubularframe 110 can be fastened to the floor panel 102 to securely butremovably mount the standby inverter generator 20 to the standby housing100.

The alternator stand 108 can be a molded or bent sheet metal housingdefining a mounting flange 109 and an alternator seat 111 offset fromthe mounting flange 109. The mounting flange 109 defines a series ofapertures that can receive one or more fasteners to mount and secure thealternator stand 108 to the floor panel 102. In some examples, thealternator stand 108 has an open end 113 that extends upwardly away fromthe floor panel 102 to define a fluid flow path into and through acavity 115 formed beneath the alternator seat 111. With the alternatorstand 108 positioned along an edge of the floor panel 102, the open end113 of the alternator stand 108 can serve as a cooling air intake flowpath that funnels and directs air entering the standby housing 100inward, beneath the alternator stand 108, and into or along the outersurface of the alternator 24 to provide cooling. To maximize the coolingair intake through the open end 113 of the alternator stand 108, thealternator stand 108 (and standby inverter generator 20) can bepositioned so that the open end 113 faces a prevailing wind direction(e.g., the open end 113 faces westward). In some examples, a fan (notshown) is provided within the cavity 115 to further drive cooling airupward into and along the alternator assembly 24 and toward the engine22 and inverter 106.

The tubular frame 110 can include one or more sections 112 of tubingthat are bent into a desired shape to suspend and support a portion ofthe standby inverter generator. For example, the tubular frame 110 canbe formed from two symmetrical (e.g., identical) and opposing sections112 that are positioned adjacent one another on the floor panel 102. Insome examples, an end of each section 112 of the tubular frame isdesigned to telescope with an opposing end of the other section 112 tocreate a secure yet releasable coupling between the sections 112.

As depicted in FIGS. 1-3 and 5-6 , each section 112 of the tubular frame110 defines two legs 114 and a mounting support 116 that extendsupwardly away from the legs 114. The legs 114 extend along the floorpanel 102 (e.g., coplanar with the floor panel 102) and define one ormore apertures to receive mounting hardware (e.g., fasteners) to securethe tubular frame 110 to the floor panel 102 of the standby housing 100.In some examples, the legs 114 of each section 112 of the tubular frame110 extend approximately parallel to one another. The mounting support116 of the tubular frame 110 bends upwardly away from each leg 114 to amounting height that is vertically offset from the floor panel 102. Asupport bridge 118 is formed within the mounting support 116 at themounting height and spans the horizontal distance between the legs 114.The support bridge 118 can extend approximately parallel to the floorpanel 102, and can be provided with a curvature to mimic or follow acurvature defining a perimeter of the alternator assembly 24, asexplained below.

Bosses 120 are formed along the support bridge 118 to receive andsupport the alternator assembly 24. For example, four bosses 120 can bepositioned about the support bridges 118 of the tubular frame 110. Thebosses 120 each support or otherwise receive a locating feature (e.g., afastener, dowel, an aperture, etc.) to help position the alternatorassembly 24 relative to the tubular frame 110. Threaded rods 122 (e.g.,set screws, molded bolts, captive screws, etc.) can be molded oranchored to the bosses 120 to serve as both locating and couplingfeatures that can be used to secure the standby inverter generator 20 tothe floor panel 102 of the standby housing 100. In some examples, thethreaded rods 122 are exposed, threaded sections of fasteners that areembedded into the bosses 120.

The alternator stand 108 and the tubular frame 110 together receive andsupport the engine 22, the alternator assembly 24, the controller 26,the muffler 28, and the fuel connection 30. The alternator stand 108 andtubular frame 110 are shaped to facilitate the assembly of the standbyinverter generator 20 within the standby housing 100 at a desiredlocation (e.g., a home or building where the standby inverter generator20 will be used). As explained earlier, the alternator stand 108 isfirst mounted to the floor panel 102 of the standby housing 100 at alocation in which the open end 113 of the alternator stand 108 engagesor abuts a side panel (e.g., side panel 103, shown in FIG. 2 ) of thestandby housing 100. Once the alternator stand 108 has been secured tothe floor panel 102, the tubular frame 110 can be secured to the floorpanel 102 as well. The legs 114 of the tubular frame 110 straddle thealternator stand 108. The gap between the support bridges 118 of thetubular frame 110 can be approximately centered over the circularalternator seat 111 of the alternator stand 108.

With the alternator stand 108 and tubular frame 110 mounted in place onthe floor panel 102, the alternator assembly 24 can be lowered intoposition. The alternator assembly 24 includes a generally cylindricalbody 124 defined by a cylindrical housing 126 and end caps 128, 129. Thecylindrical housing 126 has a generally smooth interior that defines acylindrical power generation cavity 130. The power generation cavity 130receives the rotor 48 and stator 46. As depicted in FIG. 5 , the coils50 of the stator 46 extend circumferentially around the outside surfaceof the power generation cavity 130. The rotor 48 extends into the powergeneration cavity 130 within a central recess 132 defined by the coils50 that is coaxial with the crankshaft axis 44. The external surface ofthe cylindrical body 124 includes a series of cooling fins 134 thatextend along the body 124 approximately parallel to the crankshaft axis44. In some examples, the underside of the cylindrical housing 126(e.g., the portion of the housing 126 supported on the alternator seat111) and the alternator seat 111 can define one or more passages toreceive and direct cooling airflow from the cavity 115 beneathalternator stand 108 upward into and around the alternator assembly 24.The cooling airflow can rise upward, through the power generation cavity130 and outwardly along the cooling fins 134 of the cylindrical housing126 to direct heat upwardly away from the alternator assembly 24.

The end cap 128 has an annular shape that can be secured to thecylindrical housing 126 to seal the alternator assembly 24. The end cap128 defines a rotor passage that is centered above the central recess132 (e.g., aligned with the crankshaft axis 44) to receive a portion ofthe rotor 48. In some examples, a portion of the rotor 48 extendsupward, through the rotor passage and outward from the alternatorassembly so that a coupling can be formed between the crankshaft 42 andthe rotor 48. The coupling formed between the crankshaft 42 and therotor 48 allows the crankshaft 42 and rotor 48 to rotate in unison(e.g., at identical angular velocities) and transmits torque on thecrankshaft 42 (e.g., from reciprocating piston 36 motion) to the rotor48. The rotor 48 and crankshaft 42 can extend collinear along thecrankshaft axis 44.

Mounting wings 136 extend outwardly from a top of the end cap 128 tohelp locate and secure the cylindrical housing 126 of the alternatorassembly 24 to the tubular frame 110. The mounting wings 136 can beequally spaced about a perimeter of the end cap 128 (e.g., positionedabout 90 degrees apart from one another) to help promote a securecoupling between the end cap 128 and the tubular frame 110. The mountingwings 136 each define a shelf 138 that extends away from a top of theend cap 128. In some examples, the shelf 138 extends approximatelyparallel to the floor panel 102 below. The shelves 138 each define ahole 140 that can be used to locate the end cap 128 and alternatorassembly 24, more generally, with the tubular frame 110. To facilitatecoupling between the alternator assembly 24 and the tubular frame 110,the holes 140 within the shelves 138 can be aligned with the threadedrods 122 protruding upwardly from the bosses 120 formed on the supportbridges 118 of the tubular frame 110. As the end cap 128 is loweredtoward the floor panel 102, the threaded rods 122 extend through theholes 140 and upwardly beyond each shelf 138. While an underside of theshelf 138 can be seated on the boss 120, the exposed portion of thethreaded rod 122 can receive a fastener 142 (e.g., a nut and lockwasher) that can be torqued to secure the end cap 128 to the tubularframe 102 to mount the alternator assembly 24 into place within thestandby housing 100. In some examples, the shelves 138 further supportengine locating features, shown as dowels 144, to help complete theassembly of the standby inverter generator 20.

As depicted in FIGS. 1-3, 5, and 7 , the shelves 138 and threaded rods122 (e.g., shanks of imbedded screws) from the bosses 120 can also beused to mount and secure the muffler 28 to the tubular frame 110 and thestandby inverter generator 20. A bracket 146 is mounted to a top side ofthe muffler 28 to mount the muffler 28 in a location spaced apart fromother heat generating or heat sensitive components (e.g., the engine 22and the alternator assembly 24). Accordingly, the bracket 146 can serveas a heat shield to prevent the transfer of heat within the muffler 28to the engine 22 that may otherwise cause damage to wear parts withinthe engine 22 (e.g., engine crankshaft oil seals, etc.). The bracket 146also provides a pathway for cooling air to approach the muffler 28 frommultiple directions simultaneously. The bracket 146 is defined by anH-shape that includes two mounting tabs 148 coupled to a top of themuffler 28. Legs 150 extend upwardly and perpendicularly away from themounting tabs 148. Arms 152 then extend outwardly and perpendicularlyaway from the legs 150. The spacing between the arms 152 can be variable(e.g., the spacing changes as the arms 152 extend away from the legs150). As depicted in FIG. 7 , the arms 152 taper outwardly away from oneanother to achieve a spacing that is approximately equal to the spacingbetween the bosses 120 on the tubular frame 110. Holes 154 are formedthrough distal portions of the arms 152 to receive the threaded rods122. Accordingly, two of the threaded rods 122 and nuts may be used tosupport and secure both the bracket 146 and the mounting wings 136 ofthe end cap 128 to the tubular frame 110 simultaneously.

The muffler 28 includes a generally cylindrical body 156 that defines amuffler chamber 158. The generally cylindrical body 156 extends along amuffler axis 157 that is approximately (e.g., within 5 degrees)perpendicular to the crankshaft axis 44. Conduits 160 (e.g., hoses,pipes, tubes) extend away from the muffler chamber 158 to fluidly couplethe muffler 28 with the cylinder heads 38 of the engine 22. Exhaustgases from combustion within the cylinders 34 are pushed by the piston36 outward from the cylinder head 38, through the conduits 160, and intothe muffler chamber 158. Within the muffler chamber 158, the exhaustgases are passed through a series of baffles or other sound mufflingdevices (e.g., tubes, resonating chambers, etc.) that help dampen anddissipate noise generated by the engine 22. After passing through themuffler chamber 158, the exhaust gases are directed outward from thestandby inverter generator 20 through an exhaust pipe 162 extendingoutwardly away from the cylindrical body 156, and into the externalenvironment (or within the standby housing 100). In some examples, anexhaust port 163 (shown in FIG. 11 ) is formed within one of the sidepanels 103 of the standby housing 100 to release the exhaust gases fromthe exhaust pipe 162 outward from the standby housing 100 to alleviateheat within the standby housing 100.

Referring now to FIGS. 1-5 and 9 , the engine 22 is shown. The engine 22generally includes an engine housing or blower housing 164 that definesan engine cavity 166. The engine block 32 of the engine 22 is at leastpartially received within the engine cavity 166 and is at leastpartially covered by the engine housing 164. The engine housing 164 canfurther define a battery box 168. The battery box 168 can be positionedbetween the cylinders 34 within the engine block 32, and can be used tohouse an on-board battery (e.g., battery 169, shown in FIG. 10 ). Theon-board battery can be an absorbent glass mat (AGM) battery, forexample, which supplies electrical power to the spark plugs to ignitethe fuel and air mixture within the cylinders 34 to start the engine 22.In some instances, the battery can also be used as a booster to helpsupply electricity when a spike in generator load is requested. Thebattery can supply DC electrical power to the inverter 106, which canthen be inverted to AC power and output for use. The battery box 168 canbe positioned between the cylinders 34 and proximate the cylinder heads38, which simplifies the electrical flow path between the battery andthe spark plugs within the cylinder heads 38. Various other electronicscan be positioned within the battery box 168 as well.

With additional reference to FIG. 11 , the standby housing 100 is shownin additional detail. As explained above, the standby housing 100generally includes a floor panel 102, side panels 103 extending upwardlyaway from the floor panel 102, and a cover 105 that together define acavity. The floor panel 102, side panels 103, and cover 105 togethersurround the standby inverter generator 20 to protect the standbyinverter generator 20 from the external environment (e.g., dust, rain,wind, etc.) In some examples, one or more of the side panels 103 definecooling air intakes to help direct cooling air from the externalenvironment into cavity and along the various components of the standbyinverter generator 20. As depicted in FIG. 11 , the side panel 103 caninclude separate air intakes 172, 174 for the alternator assembly 24 andthe engine 22. The air intakes 172, 174 can be spaced apart from oneanother vertically along the side panel 103. In some examples, the airintakes 172, 174 perform an air filtration function as well. The airintakes 172, 174 can be provided with filters or can be defined by oneor more louvered panels to restrict the inward flow of contaminantsthrough the side panel 103 and into contact with the standby invertergenerator 20. In some examples, the floor panel 102 is fortified by oneor more pieces of bar stock (not shown) that help maintain rigiditywithin the floor panel 102, particularly during travel.

The controller 26 and inverter 106 are coupled to the engine housing164. As depicted in FIGS. 3, 5, and 9-10 , the controller 26 andinverter 106 are positioned above the engine block 32 and above theengine 22, generally. By placing the inverter 106 and controller 26above the engine 22, the cooling airflow around these components can bemaximized. Cooling air entering through the top of the standby housing100 (e.g., within holes within the side panels 103 or beneath the cover105) will be directed over and past the inverter 106 and controller 26to remove heat generated by these components. Simultaneously, thecooling air entering from the bottom of the standby housing 100 will bedirected upward as it heats up, and will once again pass over theinverter 106 and controller 26 as it rises and exits the standby housing100. In some examples, the inverter 106, alternator assembly 24, andengine 22 all have separate air intakes. In some examples, once coolingair has passed over the inverter 106 and/or engine 22 and alternatorassembly 24, the warmer air can exit through the air intakes 172, 174formed in the side panel 103. As depicted in FIG. 3 , two of the sidepanels 103 can serve as cooling air inlets, while the remaining sidepanels 103 (e.g., the side panel 103 that includes the exhaust port 163)can serve as cooling air outlets.

The controller 26 is in communication, generally, with the engine 22 andfuel delivery systems (e.g., fuel injectors receiving fuel from a fueltank coupled to the fuel connection 30), as well as with variousexternal sources. The controller can interact with and adjust a rate offuel supply to the internal combustion engine 22 to adjust the speed ofthe internal combustion engine 22. In some examples, the controller 26can be supplied with power from the battery within the battery box 168,so that the controller 26 remains active regardless of the currentoperational status of the engine 22. The controller 26 can also beprovided with a control wire or signal in communication with anassociated building power line, which can allow the controller 26 toactively monitor the power consumption within the building that thestandby inverter generator 20 is associated with. If the controller 26detects a surge or interruption in the power supply within the building,the controller 26 can initiate an ignition sequence for the engine 22 tobegin operating.

The controller 26 is configured to operate the standby invertergenerator 20 in various different modes to improve efficiency anddecrease fuel consumption, noise, and emissions relative to conventionalstandby generators. Because the controller 26 is in communication withthe control wire or signal from the building, the controller 26 canmonitor the requested or required load to power devices within thebuilding. Accordingly, the controller 26 optimizes the operation of theengine 22 so that only the necessary amount of power is outputted by theinverter generator 20 at a given time. By adjusting the engine speed andoutput, the controller 26 can operate the engine 22 so that the amountof AC electrical power generated by the standby inverter generator 20 iscorrelated to the requested load. In some examples, the controller 26controls the standby inverter generator 20 to output an amount of ACelectrical power that is greater than the current requested load by athreshold amount (e.g., 10% or 20% more) to accommodate additional powerrequests that may occur within the building instantaneously. The engine22 is not governed at a specific angular velocity, which allows thestandby inverter generator 20 to avoid waste and eliminates unnecessaryfuel consumption and noise production.

The controller's 26 ability to adjust engine speed and output enablesthe use of different operational modes that further improve theefficiency of the standby inverter generator 20 while lowering the fuelconsumption, emissions, and noise production. Under normal loadingconditions, the controller 26 controls the engine 22 so that the pistons36 within the cylinders 34 alternate and reciprocate to drive thecrankshaft 42. The engine speed can be adjusted upward or downward byadjusting the rate of fuel delivery into the cylinders 34 in order tomeet power load demands. In some examples, the controller 26 can beconfigured to operate the engine 22 to accommodate very low power loaddemands. When the requested power load is below a certain thresholdvalue (e.g., less than 30% of maximum output of the standby invertergenerator 20, etc.) the controller 26 may control the engine 22 so thatonly one of the two cylinders 34 operates. Accordingly, fuel will onlybe delivered to one of the two cylinders 34, and battery power will onlybe supplied to the spark plug positioned in one of the two cylinderheads 38. With only one of two cylinders 34 operating, the torque androtational speed of the crankshaft and, as a result, the rotor 48 willbe reduced. However, the controller 26 can maintain the engine speedsuch that even with a single cylinder 34 firing, the rotor 48 generatesAC electrical power that can be supplied to the rectifier 104 andinverter 106 and outputted at the desired frequency and voltage.Accordingly, the controller 26 can control the engine to operate at muchlower speeds (e.g., 1400 rpm) than conventional generators to stilloutput the necessary amount of AC electrical power.

The selective operation of the cylinders 34 can also be used by thestandby inverter generator 20 to execute “exercise mode” operations tomaintain the readiness of the standby inverter generator 20.Periodically (e.g., once a week, once a month, once a quarter, etc.) thecontroller 26 can transition the standby inverter generator 20 toexercise mode in order perform routine exercise procedures. In theexercise mode, the controller 26 once again controls the engine 22 sothat only a single cylinder 34 is operating. Alternatively, the engine22 can be operated at a much lower frequency (e.g., 1400 RPM, 1800 RPM,etc.) using both cylinders 34. The lower output of the engine 22 andreduced angular velocity of the crankshaft 42 and rotor 48 can cyclefuel through the fuel system of the standby inverter generator 20 andgenerate an amount of electrical power that is below a rated capacity ofthe standby inverter generator 20. The electrical power generated by thestandby inverter generator 20 in the exercise mode can be sufficient topartially or fully recharge the battery within the engine housing 164.Accordingly, the electrical power generated by the alternator assembly24 can be provided to the rectifier 104 and diverted to the battery,rather than output through the inverter 106.

The controller 26 can activate or transition the standby invertergenerator 20 to the exercise mode in a variety of ways. For example, thecontroller 26 may monitor the crankshaft 42. If a threshold time periodhas elapsed (e.g., one week, one month, 90 days, etc.) where thecrankshaft 42 has remained idle, the controller 26 can initiate theexercise mode. The controller 26 can activate an ignition sequence bydrawing electricity from the battery to power the fuel delivery systemand spark plugs within one of the two cylinders 34. Once combustion hasoccurred within the cylinder 34 and the crankshaft 42 begins rotating,the power to operate the fuel delivery system and spark plugs can bediverted from the rectifier 104 to continue operation of the standbyinverter generator 20. The controller 26 can continue to operate theengine 22 in the exercise mode until a threshold time period (e.g.,fifteen minutes, one hour, etc.) has elapsed. Upon receiving anindication that the threshold time period has elapsed, the controller 26can command the internal combustion engine 22 to cease operating. Insome examples, the controller 26 disconnects the fuel delivery systemand spark plugs from an electrical power supply to effectively shut downthe engine 22.

The controller 26 can also be configured to output AC electrical powerat different frequencies to accommodate different electrical powerneeds. By controlling the engine speed, the controller 26 effectivelycontrols the angular velocity of the rotor 48. The relationship betweenthe rotor 48 and stator 46 is such that varying the angular velocity ofthe rotor 48 can change the characteristics of the signal being outputby the alternator assembly 24. In some examples, the inverter 106 isfurther configured to accept the DC electrical power from the rectifier104 and invert the DC electrical power to clean 50 Hz AC electricalpower. The inverter 106 can communicate with the controller 26 to adjustengine speed to accommodate a desired output characteristic of theelectrical power from the standby inverter generator 20. The standbyinverter generator 20 does not experience any derating due to the enginespeed changes. Accordingly, the standby inverter generator 20 can beused in various locations and may be cross-compatible in both the UnitedStates and throughout several countries of the world.

The controller 26 can also be provided with preset operationalparameters that can be selected by a user. For example, the engine 22 ofthe standby inverter generator 20 can be compatible with several fueltypes (e.g., natural gas, propane, gasoline, etc.). Because the fuelsources have different relative energy densities, the rate of fueldelivery may differ across fuel types. In order to achieve the same (orsimilar) AC electrical power output from the standby inverter generator20, the controller 26 (or an actuator or display) may prompt a user toselect a fuel source type. The selection can be made by moving oractuating a button or otherwise making a selection via a display that isin communication with the controller 26. Upon receiving a selection, thecontroller 26 can access a memory 170 (e.g., an on-board memory orcloud-based memory), which stores operational parameters associated withthe selected fuel source. The controller 26 can then communicate withthe fuel delivery system and spark plugs of the engine 22 to providefuel and perform combustion at a frequency necessary to drive thecrankshaft 42 and rotor 48 at an angular velocity sufficient to generatethe desired electrical load.

Although shown as a singular unit, the standby inverter generator 20 canbe included in series or in parallel with additional standby invertergenerators 20 to increase the total power generation capacity for abuilding. For example, two 6.5 kW rated standby inverter generators canbe positioned in parallel to increase the power delivery capability ofthe standby inverter generators 20. Each standby inverter generator 20can be provided with its own controller 26 or, alternatively, a singlecontroller 26 can control both units. In some examples, one standbyinverter generator 20 includes a master controller 26 that cancommunicate with a slave controller on the one or more additionalstandby inverter units coupled together. In some examples, the standbyinverter generator 20 is a 9.5 kW unit.

Referring now to FIGS. 12-18 , another standby inverter generator 220 isdepicted. The standby inverter generator 220, like the standby invertergenerator 20, includes an internal combustion engine 22, an alternatorassembly 24, a controller 26, and a muffler 28. The inverter generator220 is positioned within and coupled to a standby housing 300, which isconfigured to be positioned alongside a home or building. As depicted inFIGS. 13-17 , the inverter generator 220 is coupled to a floor panel 302of the standby housing 300. A fuel connection 30 can be positioned neara perimeter of the floor panel 302, and can extend through the standbyhousing 300 to form a coupling with a fuel source, like compressednatural gas, propane, gasoline, or other suitable energy source. Asdepicted in FIG. 14 , the fuel connection 30 can include a flowregulator to help meter the flow of fuel from a nearby fuel source (notshown) into the internal combustion engine 22. The controller 26 (whichincludes the inverter 106) extends at least partially above the internalcombustion engine 22 and alternator assembly 24, and approximatelyparallel to an outer surface of the standby housing 300.

The standby inverter generator 220 has a compact design that reduces theoverall footprint of the system relative to conventional generators. Forexample, and as depicted in FIG. 16 , the alternator assembly 24 isdefined by a height that is less than half a height defining the engineblock 32. By reducing the height of the alternator assembly 24, theinternal combustion engine 22 can be positioned lower to the floor panel302, which can further promote cooling.

The standby inverter generator 220 and its associated standby housing300 are designed to improve airflow and cooling of the variousheat-generating components within the standby inverter generator 220. Asdepicted in FIGS. 13-17 , the alternator assembly 24 and internalcombustion engine 22 are each suspended off of the floor panel 302 toallow airflow beneath the components. Like the inverter generator 20,the inverter generator 220 also includes an alternator stand 108 that isconfigured to permit airflow beneath the alternator assembly 24. Theinternal combustion engine 22 is suspended away from the floor panel 302by a frame, shown as support structure 280, that is formed of acombination of support bars 282 and one or more panels 284. The supportbars 282 can be bent, welded, or otherwise formed into a shape thatprovides a support surface 286 that extends approximately parallel tothe floor panel 302. The support surface 286 can include one or morebosses 288 that are used to mount the engine block 32 to the floor panel302. In some examples, the one or more panels 284 can be formed toextend around the engine block 32 to serve as a heat shield between themuffler 28 and the internal combustion engine 22 and alternator assembly24.

The standby inverter generator 220 is designed to direct cooling airinto and through the different heat generating components. As depictedin FIG. 18 , the standby housing 300 is formed of panels 304 and a roof306. The panels 304 extend away from the floor panel 302 and can supporta series of vents, shown as grilles 308 that allow air to enter into thestandby housing 300. In some examples, the grilles 308 include one ormore louvered panels that are designed to filter out contaminants fromcooling air prior to entering into the standby housing 300.

The primary air flow pattern through the standby housing 300 directscooling air over the controller 26 and inverter 106 first, to theelectrical panel 290, and then down into and toward the internalcombustion engine 22 and out of the standby housing 300. As depicted inFIG. 14 , air is first directed through a grille 308 formed in a panel304 toward the controller 26 and inverter 106. The high electricalloading of these components generates a significant amount of heat thatis advantageously removed from the system. By directing the primaryairflow through the standby housing 300 toward the inverter 106 andcontroller 26 first, ambient air will contact the inverter 106 andcontroller 26 when the air is at its coolest temperature. Accordingly,air having the greatest capacity for cooling the system will be directedover the most heat-sensitive components first.

The cooling air passes toward the inverter 106 and controller 26 and isheated as the air passes over these components. As the air warms andcarries heat away from the inverter 106 and controller 26, the air riseswithin the standby housing 300. A passage is formed above the inverter106 and controller 26 that directs this air toward the electrical panel290 that extends above the internal combustion engine 22 and alternatorassembly 24. As depicted in FIG. 15 , the electrical panel 290 issuspended above the internal combustion engine 22 and separated from theinternal combustion engine 22 by an air gap 292. The air gap 292 can bedefined by a tray 294 that receives the electrical panel 290 and a heatshield 296 extending above the internal combustion engine 22. The tray294 and the heat shield 296 can extend approximately parallel to oneanother and approximately parallel to the floor panel 302.

The heated air passes over electrical panel 290, toward a recess 298formed within the tray 294 and through the heat shield 296, as depictedin FIG. 15 . The heated air then travels downward, through the tray 294and the heat shield 296, and to the internal combustion engine 22. Theoperation of the internal combustion engine 22 can create a low pressurearea near the internal combustion engine 22 which urges the airdownward. In some examples, a portion of the cooling air can be used bythe internal combustion engine 22 to execute the combustion reaction todrive the engine 22. The remaining cooling air can pass along theexterior of the engine block 32 and the alternator assembly 24 to carryheat away from these components. Additional grilles 308 can be formedwithin the panels 304 to direct the cooling air outward from the standbyhousing 300, and back to the external environment. Using the primarycooling path, the most heat-sensitive heat generating components can beprovided with external cooling air first, which can help to promote amore effective cooling process.

Referring now to FIG. 18 , the standby housing 300 is configured toprovide easy access to the various electrical components of the standbyinverter generator 220. In some examples, the roof 306 is designed to beremovable from the rest of the enclosure. In addition to the roof 306being removable, one or more of the panels 304 can be designed toprovide access into the inverter 106 and/or controller 26. For example,the panel 310 extending in front of the inverter 106 and controller 26can be rotatably coupled to the rest of the standby housing 300. Thepanel 310 can be supported by hinge joints 312 that allow the panel 310to rotate relative to the roof 306 or relative to the other panels 304,to a position that permits access to the inverter 106 and controller 26positioned nearby.

Using the aforementioned controller 26, the engine 22 can be controlledto accommodate varying electrical power loads in a manner that avoidsexcess fuel consumption or unused power. By controlling the engine speedto mirror (or slightly overshoot) the required power output, the enginecan run at lower speeds when appropriate, which reduces the amount ofnoise and fuel emissions outputted by the standby inverter generator. Byfurther controlling the engine to fire only one of two cylinders 34 incertain situations, the emissions and noise can be further limited.Significant efficiency gains result from the low power exercise modecarried out by the controller 26 and engine 22. The engine 22 andcontroller 26 also enable the standby inverter generator to operate onmultiple different fuel sources effectively.

Various other advantages are achieved by the standby inverter generator20 disclosed. The alternator assembly 24 has a high frequency output,which allows the overall standby inverter generator to be shorter (e.g.,by about 6 inches). The height reduction in turn allows the inverter 106and associated controller 26 to be positioned above the engine 22, in aposition where it is easier to access and more directly within the flowpath of cooling air from multiple directions. The inverter 106 canprovide clean AC electrical power at different frequencies toaccommodate different loading. Similarly, the vertical orientation ofthe crankshaft 42 reduces the horizontal footprint of the standbyinverter generator 20, allowing for smaller standby housings 100 to beused. In some examples, the floor panel 102 is reinforced to allow thestandby housing 100 and standby inverter generator 20 to be moved usinga standard dolly.

Referring now to FIGS. 19-22 and 23 , another exemplary embodiment of astandby inverter generator 420 is depicted. The standby invertergenerator 420 may be substantially similar to the standby invertergenerator 2 except as described herein. For example, the standbyinverter generator 420 includes an internal combustion engine 422, analternator assembly 424, a controller 426, an intake manifold 430, and amuffler 428. In some embodiments, the controller 426 may be within thealternator housing 423 of the alternator assembly 424 and not visible.The inverter generator 420 is positioned within and coupled to a standbyhousing 500, which is configured to be positioned alongside a home orbuilding. The inverter generator 420 sits on a frame 510 that is coupledto a floor panel 502 of the standby housing 500. The frame 510 isconfigured to couple the internal combustion engine 422 to the floorpanel 502 and to separate each of the other components of the standbyinverter generator 420. The side walls and upper panel of the standbyhousing 500 are not shown. A fuel connection can be positioned near aperimeter of the floor panel 502, and can extend through the standbyhousing 500 to form a coupling with a fuel source, like compressednatural gas, propane, gasoline, or other suitable energy source. Inother embodiments, the fuel connection can be positioned in otherlocations.

FIGS. 20 and 21 are perspective views of the internal combustion engine422 and the alternator assembly 424 of the standby inverter generator420 in different orientations. FIG. 22 shows an exploded perspectiveview of the internal combustion engine 422 and alternator assembly 424in the orientation shown in FIG. 21 . The alternator housing 423 is notshown in FIGS. 20, 21, and 22 . The alternator assembly 424 of thestandby inverter generator 420 is positioned above and is coupled to theinternal combustion engine 422. Referring now to FIG. 22, the alternatorassembly 424 includes a stator 446 and a rotor 448. The crankshaft 442of the internal combustion engine 422 extends through the stator 446 andis coupled to the rotor. As described above, the rotor 448 rotates withthe crankshaft 442 and the rotating rotor magnets generate a magneticflux that induces an electrical current in the coils 450 of the stator446, generating alternating current electrical power. The alternatingcurrent electrical power is directed to the controller 426, whichincludes a rectifier 504 and an inverter 506, for selectively convertingthe alternating current electrical power into direct current electricalpower and back to stable alternating current electrical power.

The alternator assembly 424 includes a fan 451 positioned above andcoupled to the rotor 448, e.g., via a plurality of fasteners 453. Thefan 451 pulls in air from above the standby inverter generator 420 andpushes it down through the alternator assembly 424 to an air intake ofthe internal combustion engine 422. The rotor 448 may include aplurality of openings 455 configured to allow air to pass through therotor 448 to the internal combustion engine 422. At least a portion ofthe air is used in the combustion of fuel in the cylinders 434 internalcombustion engine 422. The air moved through the alternator assembly 424by the fan 451 also acts to cool the alternator assembly 424 and theinternal combustion engine 422 without the need for additional fans,blowers, or ducting. Exhaust from the cylinders 434 is directed to themuffler 428, which reduces the sound generated by the internalcombustion engine 422. The muffler 428 is positioned below the internalcombustion engine 422. Air flow generated by the fan 451 may also coolthe muffler 428.

In some embodiments, the alternator assembly 424 may be operated as astarter motor to provide the initial rotation of the crankshaft 442required to start the engine 422. The coils 450 in the stator 446 of thealternator assembly 424 draw power from a battery (not shown),generating an electromagnetic field. The electromagnetic field causesthe rotor 448 of the alternator assembly 424 to rotate. Thus, thealternator assembly 424 essentially operates in reverse to generaterotation of the rotor 448 using electricity, rather than generatingelectricity from the rotation of the rotor 448 by the internalcombustion engine 422. Because the rotor 448 is coupled to thecrankshaft 442, the crankshaft 442 rotates with the rotor 448, whichcauses the pistons of the cylinders 434 to reciprocate. The internalcombustion engine 422 can then begin operate as described above, byigniting an air and fuel mixture in the cylinders 434 using spark plugsto fire the pistons and rotate the crankshaft 442. The alternatorassembly 424 can then stop operating as a starter motor and begin tooperate as an alternator to generate electricity from the rotation ofthe crankshaft 442 by the engine 422 following a set period of time, inresponse to threshold engine speed, and/or in response to anotherindication the engine 422 has been started.

The controller 426 (shown in FIG. 19 ) can be configured to control therotational speed of the rotor 448 when starting the engine 422. Asdiscussed above with reference to the generator 20, during operation ofthe generator 420, the controller 426 can be configured to control thespeed of the engine 422 to match the required power demand (e.g., theelectrical load) on the generator 420. The controller 426 can similarlybe configured to control the starting speed of the rotor 448 and thusthe crankshaft 442 during startup so that the engine speed canimmediately match the power demand when the generator 420 starts. Thisallows for a more seamless transition from grid power to generator powerand can reduce noise at startup compared to using startup speed set to amaximum speed. As described above with respect to the controller 26, thecontroller 426 also comprises a rectifier 504 and an inverter 506respectively configured to convert the AC power from the generator 20 toDC power, and back to a cleaner (e.g., higher quality) and more widelyuseful AC electrical power at a desired frequency and voltage (e.g., 120VAC at 60 Hz).

The controller 426 can also be configured to control the sparkgeneration timing of the spark plug (not shown). For example, thecontroller 426 can be configured to delay the spark plug timing atslower speeds such that the cylinders 434 fire near top dead center. Athigher speeds, the controller 426 can be configured to fire earlier thanwhen the cylinders 434 are at top dead center. This allows for moreefficient use of fuel and operation of the engine 422. The controller426 can be electrically coupled to the spark plugs and can sendelectricity to the spark plug to generate a spark. Because the rotor 448is coupled to the crankshaft 442, the position of the rotor 448 can beused to determine the position of the pistons. For example, thealternator assembly 424 may include a rotor position sensor that iscommunicatively coupled to the controller 426 and configured to detectthe position of the rotor 448. The controller 426 may receive rotorposition data from the rotor position sensor and may use the rotorposition data to determine when to fire the spark plugs. When startingthe internal combustion engine 422, the controller 426 may control thespark generation timing of the spark plug based on the starting speeddetermined as described above.

The spark plug firing timing can also be adjusted based on fuel type.For example, the generator 420 may be configured to run on bothliquefied petroleum (LP) and natural gas (NG). Because these fuels mayburn and expand at different rates, the timing of spark plug firingsneeds to be adjusted to ensure efficient operation of the engine 422. Asshown in FIG. 19 , the generator 420 may include a switch 465 (e.g.,rocker switch, knob, button, etc.) that allows a user to input whetherthe fuel used is LP, NG or some other fuel (e.g., gasoline). FIG. 24 isa schematic view of the standby inverter generator 420, including theswitch 465. The controller 426 may receive a signal from the switch 465and may adjust the timing of the spark plug firings based on the signalreceived. In some embodiments, the switch 465 may also enable the flowof one type of fuel while disabling the flow of another type of fuel.For example, moving the switch 465 to the NG position may open a firstvalve that allows NG from an NG supply to flow into the cylinders 434and may close a second valve, stopping LP from flowing into thecylinders 434. Moving the switch 465 may physically open and close thevalves or may send an electrical signal causing the valves to open andclose. The switch 465 may be positioned on the alternator housing 423,on a fuel line remote from the generator 420, or elsewhere in thegenerator 420. As discussed above, moving the switch 465 may act to bothdetermine the fuel type allowed to reach the cylinders 434 and send anindication of the selected fuel type to the controller 426. Fuel flowinto the cylinders 434 may be governed by a regulator and/or anelectronic fuel injector. As described above, the alternator 424generates AC power 425, which is directed the rectifier 504 withincontroller 426. The rectifier 504 generates DC power 427. The DC power427 is directed to the inverter, which converts the DC power from therectifier 504 to stable AC power 429 suitable for use in a home or otherbuilding. Some of the DC power 427 may be directed to a battery 569 forlater use.

In some embodiments, the generator 420 may include a sensor configuredto detect the type of fuel being delivered to the engine 422. Forexample, the sensor may be a chemical sensor configured to detect levelsof certain components of the fuel. The controller 426 may becommunicatively coupled to the sensor and configured to receive a signalfrom the sensor indicating the fuel type. The controller 426 can adjustthe timing of the spark plug firings based on the signal received fromthe sensor. In other embodiments, the fuel type may be input via adigital user control panel.

Referring still to FIG. 24 , in some embodiments, the inverter 506delivers the stable AC power 429 to a transfer switch 2402. The transferswitch 2402 may also be configured to receive power from the electricalgrid 2404, a solar panel system 2406, and a battery 2408. The transferswitch 2402 is configured to switch between the various power sources tosupply power to the building 2410. For example, if grid power 2404 fails(e.g., during a blackout) and no power is available from the solarpanels 2406 (e.g., at night), the transfer switch may supply power formthe battery 2408 and/or the standby inverter generator 420 to thebuilding 2410. In some embodiments, the transfer switch 2402 may beconfigured to allow the standby inverter generator 422, the grid power2404, and/or the solar panels 2406 to charge the battery 2408. In someembodiments, the transfer switch 2402 may be referred to as a componentof the inverter generator 422. In some embodiments, the transfer switch2402 is configured to be attached to a building 2410 and is attached tothe building 2410 when the standby inverter generator 420 is installedon site. For example, the transfer switch 2402 may be attached to a wallof the building 2410 near the building's circuit breaker panel.

FIG. 25 illustrates a method 2500 of controlling a standby invertergenerator (e.g., standby inverter generator 420). The method may beperformed, for example, by controller 426. At operation 2502 of method2500, an indication of a power demand form a load source is received.For example, the controller 426 may receive an indication of a powerdemand from a building. The indication may also signal the controller426 to start the internal combustion engine 422. At operation 2504 ofmethod 2500, an indication of a fuel type is received. For example, thecontroller 426 may receive an indication of a fuel type from the switch465 or from a fuel type sensor. At operation 2506 of method 2500, astarting speed of the engine is determined based on the power demand.For example, the controller 426 may control the starting speed of theengine 422 such that the standby inverter generator 420 produces theappropriate amount of power to meet the power demand of the building. Atoperation 2508 of method 2500, spark plug timing for the engine isdetermined based on the fuel type. For example, as described above, thecontroller 426 may determine the spark plug timing based on whether thefuel source is LP, NG, or gasoline. At operation 2510 of method 2500,the motor is started using the determined engine starting speed andspark plug timing. For example, the controller 426 may start theinternal combustion engine 422 using the determined starting speed andspark plug timing. Once started, the engine 422 can continue to runusing the determined starting speed and spark plug timing. At operation2512 of method 2500, the engine speed is adjusted based on changed tothe power demand. For example, when the load on the building increasesor decreases, the controller 426 can adjust the engine speed to suchthat the standby inverter generator 420 produces the appropriate amountof power to meet the new power demand.

Referring now to FIG. 23 , another exemplary embodiment of a standbyinverter generator 620 is depicted. The standby inverter generator 620includes an internal combustion engine 622. The internal combustionengine 622 is a single cylinder, horizontal shaft engine. In otherembodiments of a standby inverter generator, the internal combustionengine may be a multiple cylinder horizontal shaft engine, for example,a v-twin horizontal shaft engine. In still other embodiments of astandby inverter generator, the internal combustion engine may be asingle cylinder vertical shaft engine. The internal combustion engineincludes a single cylinder 634 and a crankshaft 642. The standbyinverter generator 620 is positioned within and coupled to a standbyhousing 700, which is configured to be positioned alongside a home orbuilding. The standby inverter generator 620 sits on a frame 710 that iscoupled to a floor panel 702 of the standby housing 700. The frame isconfigured to couple the internal combustion engine 622 to the floorpanel 702 and to separate each of the other components of the standbyinverter generator 620. The side walls and upper panel of the standbyhousing 700 are not shown. However, the standby housing 700 may besubstantially similar to the standby housing 100 shown in FIGS. 11 and12 . A fuel connection can be positioned near a perimeter of the floorpanel 702, and can extend through the standby housing 700 to form acoupling with a fuel source, like compressed natural gas, propane,gasoline, or other suitable energy source. A muffler 628 is coupled tothe frame 710 under the internal combustion engine 622. In otherembodiments, the muffler 628 may be positioned next to the internalcombustion engine 622, e.g., on the opposite side of the crankshaft 642.The standby housing 700 is similar to and can include the samecomponents as the standby housings 100 and 300.

Like the standby inverter generator 420, the standby inverter generator620 includes an alternator assembly 624, including a stator 646 and arotor 648. The crankshaft 642 of the internal combustion engine 622extends through the stator 646 and is coupled to the rotor 648. Asdescribed above, the rotor 648 rotates with the crankshaft 642 and therotating rotor magnets generate a magnetic flux that induces anelectrical current in the coils 650 of the stator 646, generatingalternating current electrical power. The standby inverter generator 620includes a controller 626 configured to control the standby invertergenerator similarly to the controller 626 of standby inverter generator420. For example, the controller 626 includes a rectifier 704 and aninverter 706 to convert the alternating current output by the alternatorassembly 624 to a clean alternating current. The controller 626 is alsoconfigured to control spark plug timing, control the speed of the engine622 in response to a detected electrical load, and to control the rotor648 speed when the alternator assembly 624 is used to start the engine,as discussed above with respect to controller 26 and controller 426.

The alternator assembly 624 also includes a fan 651 coupled to the rotor648. The fan 651 is configured to pull in air from next to the standbyinverter generator and push the air through the alternator assembly 624to the internal combustion engine 622. The engine 622 may draw in aportion of the air to be used in the combustion of fuel in the cylinder634 internal combustion engine 622. The airflow from the fan 651 mayalso cool the alternator assembly 624, engine 622, and muffler 628.

Although this description may discuss a specific order of method steps,the order of the steps may differ from what is outlined. Also, two ormore steps may be performed concurrently or with partial concurrence orcertain method steps may not be performed. Such variation will depend onthe software and hardware systems chosen and on designer choice. Allsuch variations are within the scope of the disclosure. Likewise,software implementations could be accomplished with standard programmingtechniques with rule-based logic and other logic to accomplish thevarious connection steps, processing steps, comparison steps, anddecision steps.

As utilized herein, the terms “approximately”, “about”, “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claims.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like, as used herein, mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent, etc.) or moveable (e.g.,removable, releasable, etc.). Such joining may be achieved with the twomembers or the two members and any additional intermediate members beingintegrally formed as a single unitary body with one another or with thetwo members or the two members and any additional intermediate membersbeing attached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” “between,” etc.) are merely used to describe theorientation of various elements in the figures. It should be noted thatthe orientation of various elements may differ according to otherexemplary embodiments, and that such variations are intended to beencompassed by the present disclosure.

The construction and arrangement of the standby inverter generator asshown in the exemplary embodiments is illustrative only. Although only afew embodiments of the present disclosure have been described in detail,those skilled in the art who review this disclosure will readilyappreciate that many modifications are possible (e.g., variations insizes, dimensions, structures, shapes and proportions of the variouselements, values of parameters, mounting arrangements, use of materials,colors, orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements. It should be noted that the elements and/or assemblies ofthe components described herein may be constructed from any of a widevariety of materials that provide sufficient strength or durability, inany of a wide variety of colors, textures, and combinations.Accordingly, all such modifications are intended to be included withinthe scope of the present inventions. Other substitutions, modifications,changes, and omissions may be made in the design, operating conditions,and arrangement of the preferred and other exemplary embodiments withoutdeparting from scope of the present disclosure or from the spirit of theappended claims.

What is claimed is:
 1. A generator comprising: an internal combustion engine comprising: an engine block including a cylinder comprising a piston; a crankshaft coupled to the engine block and configured to rotate about a crankshaft axis in response to movement by the piston; and a spark plug configured to periodically generate a spark to ignite fuel in the cylinder to control the movement of the piston; an alternator comprising a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power; a controller configured to control a rate of fuel supply to the internal combustion engine; and a switch configured to selectively enable the flow of a first type of fuel into the cylinder and disable the flow of a second type of fuel, wherein the switch is communicatively coupled to the controller and wherein the controller is configured to receive an indication of a fuel type based on a position of the switch.
 2. The generator of claim 1, further comprising a fan coupled to the rotor.
 3. The generator of claim 2, wherein the alternator is positioned between the internal combustion engine and the fan and coupled to the internal combustion engine, and wherein the fan is configured to draw in air and move the air through the alternator to the internal combustion engine.
 4. The generator of claim 3, wherein an air intake of the internal combustion engine is configured to receive at least a portion of the air for use in the combustion of fuel.
 5. The generator of claim 3, further comprising a muffler positioned below the internal combustion engine.
 6. The generator of claim 5, further comprising a frame configured to couple the internal combustion engine to a floor panel and to separate the alternator, the controller, the fan, and the muffler from the floor panel.
 7. The generator of claim 1, wherein the controller is configured to adjust a spark generation timing of the spark plug based on the indication of the fuel type.
 8. The generator of claim 7, wherein the switch is configured to selectively enable the flow of the first type of fuel into the cylinder by physically opening a first valve and to selectively disable the flow of the second type of fuel by physically closing a second valve.
 9. The generator of claim 1, wherein the controller comprises a rectifier configured to convert the alternating current to a direct current and an inverter configured to convert the direct current to a clean alternating current electrical power.
 10. The generator of claim 9, further comprising a transfer switch configured to receive the clean alternating current electrical power from the controller and at least one of grid power from an electrical grid, solar power from a solar panel assembly, or battery power from a battery, and configured to supply power to an electrical load.
 11. A generator comprising: an internal combustion engine comprising: an engine block including a cylinder comprising a piston; a crankshaft coupled to the engine block and configured to rotate about a crankshaft axis in response to movement by the piston; and a spark plug configured to periodically generate a spark to ignite fuel in the cylinder to control the movement of the piston; an alternator comprising a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power; a starter battery configured to supply power to the alternator, wherein the rotor is further configured to rotate the crankshaft using power from the starter battery to start the internal combustion engine; and a controller configured to: receive an indication of a fuel type; and adjust a spark generation timing of the spark plug based on the indication of the fuel type.
 12. The generator of claim 11, wherein the controller includes a rectifier configured to convert the alternating current to a direct current and an inverter configured to convert the direct current to a clean alternating current electrical power.
 13. The generator of claim 12, further comprising a transfer switch configured to receive the clean alternating current electrical power from the controller and at least one of grid power from an electrical grid, solar power from a solar panel assembly, or battery power from a battery, and configured to supply power to an electrical load.
 14. The generator of claim 11, further comprising a switch configured to selectively enable the flow of a first type of fuel into the cylinder and disable the flow of a second type of fuel into the cylinder.
 15. The generator of claim 14, wherein the switch is configured to generate the indication of the fuel type.
 16. The generator of claim 11, further comprising a sensor configured to detect the fuel type and generate the indication based on the detected fuel type.
 17. The generator of claim 11, wherein the alternator comprises a rotor position sensor communicatively coupled to the controller and configured to detect a rotational position of the rotor, and wherein the controller is configured to receive rotor position data from the rotor position sensor and adjust the spark generation timing of the spark plug based on the rotor position data.
 18. A generator comprising: an internal combustion engine comprising: an engine block including a cylinder comprising a piston; a crankshaft coupled to the engine block and configured to rotate about a crankshaft axis in response to movement by the piston; and a spark plug configured to periodically generate a spark to ignite fuel in the cylinder to control the movement of the piston; an alternator comprising a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power; a battery configured to supply power to the alternator, wherein the rotor is further configured to rotate the crankshaft using power from the battery to start the internal combustion engine; and a controller configured to: detect an electrical load; determine a starting speed of the internal combustion engine based on the detected electrical load; and control a rotation speed of the rotor based on the determined starting speed.
 19. The generator of claim 18, wherein the controller includes a rectifier configured to convert the alternating current to a direct current and an inverter configured to convert the direct current to a clean alternating current electrical power.
 20. The generator of claim 18, wherein the controller is configured to adjust a spark generation timing of the spark plug based on the determined starting speed. 